﻿/*
* Copyright (C) 2020 ~ 2024 chaigec All Rights Reserved.
*
* Author:     chaigec <chaigec@163.com>
* Maintainer: chaigec <chaigec@163.com>

 * Use of this source code is governed by MIT license that can be found in the
 * LICENSE file in the root of the source tree. All contributing project authors
 * may be found in the AUTHORS file in the root of the source tree.
*/

#include "MkMd5.h"
#include "MkUtil.h"
#include <stdlib.h>
#include <math.h>

#define DigestSizeInBytes 16
//#define DigestSizeInHexBytes (2*DigestSizeInBytes)
//#define DigestSizeAsString (DigestSizeInHexBytes+1)

#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

// Basic MD5 functions:
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

// Rotate "x" left "n" bits:
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

// Other transforms:
#define FF(a, b, c, d, x, s, ac) { \
 (a) += F((b), (c), (d)) + (x) + (Uint32)(ac); \
 (a) = ROTATE_LEFT((a), (s)); \
 (a) += (b); \
}
#define GG(a, b, c, d, x, s, ac) { \
 (a) += G((b), (c), (d)) + (x) + (Uint32)(ac); \
 (a) = ROTATE_LEFT((a), (s)); \
 (a) += (b); \
}
#define HH(a, b, c, d, x, s, ac) { \
 (a) += H((b), (c), (d)) + (x) + (Uint32)(ac); \
 (a) = ROTATE_LEFT((a), (s)); \
 (a) += (b); \
}
#define II(a, b, c, d, x, s, ac) { \
 (a) += I((b), (c), (d)) + (x) + (Uint32)(ac); \
 (a) = ROTATE_LEFT((a), (s)); \
 (a) += (b); \
}

static void UnpackUint32(Uint8 out[4], Uint32 in)
{
    for (Uint32 i = 0; i < 4; ++i) {
        out[i] = (Uint8)((in >> (8 * i)) & 0xFF);
    }
}

static void UnpackUint64(Uint8 out[8], Uint64 in)
{
    for (Uint32 i = 0; i < 8; ++i) {
        out[i] = (Uint8)((in >> (8 * i)) & 0xFF);
    }
}

static const Uint8 Padding[64] = {
          0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

CMkMd5Encode::CMkMd5Encode()
    : m_BitCount(0)
{
    // Initialize with magic constants:
    m_State[0] = 0x67452301;
    m_State[1] = 0xefcdab89;
    m_State[2] = 0x98badcfe;
    m_State[3] = 0x10325476;
}


MkString CMkMd5Encode::Encode(const MkString& Src, BOOL bLowLetters /*= TRUE*/)
{
    Uint8 OutputDigest[DigestSizeInBytes] = { 0 };
    CMkMd5Encode Encoder;
    Encoder.AddData((Uint8*)Src.c_str(), Src.size());
    Encoder.Finalize(OutputDigest);
    MkString ByteString;
    CMkUtil::ByteToString(OutputDigest, DigestSizeInBytes, ByteString, bLowLetters);
    return ByteString;
}

void CMkMd5Encode::AddData(const Uint8* InputData, Uint32 DataSize)
{
    Uint64 ByteCount = m_BitCount >> 3;
    Uint32 BufferBytesInUse = (Uint32)(ByteCount & 0x3F);
    Uint32 BufferBytesRemaining = 64 - BufferBytesInUse;

    m_BitCount += DataSize << 3;

    Uint32 i = 0;
    if (DataSize >= BufferBytesRemaining) {
        memcpy((Uint8*)&m_WorkingBuffer[BufferBytesInUse], (Uint8*)InputData, BufferBytesRemaining);
        Transform64Bytes(m_WorkingBuffer);
        BufferBytesInUse = 0;

        for (i = BufferBytesRemaining; i + 63 < DataSize; i += 64) {
            Transform64Bytes(&InputData[i]);
        }
    }

    if (i < DataSize) {
        memcpy((Uint8*)&m_WorkingBuffer[BufferBytesInUse], (Uint8*)&InputData[i], DataSize - i);
    }
}

void CMkMd5Encode::Finalize(Uint8* OutputBytes)
{
    Uint8 bitCountInBytes[8];
    UnpackUint64(bitCountInBytes, m_BitCount);

    Uint64 ByteCount = m_BitCount >> 3;
    Uint32 BufferBytesInUse = (Uint32)(ByteCount & 0x3F);
    Uint32 NumPaddingBytes
        = (BufferBytesInUse < 56) ? (56 - BufferBytesInUse) : (64 + 56 - BufferBytesInUse);
    AddData(Padding, NumPaddingBytes);

    AddData(bitCountInBytes, 8);

    // Unpack our 'state' into the output digest:
    UnpackUint32(&OutputBytes[0], m_State[0]);
    UnpackUint32(&OutputBytes[4], m_State[1]);
    UnpackUint32(&OutputBytes[8], m_State[2]);
    UnpackUint32(&OutputBytes[12], m_State[3]);

    Zeroize();
}

void CMkMd5Encode::Zeroize()
{
    m_State[0] = m_State[1] = m_State[2] = m_State[3] = 0;
    m_BitCount = 0;
    for (Uint32 i = 0; i < 64; ++i) {
        m_WorkingBuffer[i] = 0;
    }
}

void CMkMd5Encode::Transform64Bytes(const Uint8 Block[64])
{
    Uint32 a = m_State[0];
    Uint32 b = m_State[1];
    Uint32 c = m_State[2];
    Uint32 d = m_State[3];

    Uint32 x[16];
    for (Uint32 i = 0, j = 0; i < 16; ++i, j += 4) {
        x[i] = ((Uint32)Block[j]) | (((Uint32)Block[j + 1]) << 8) | (((Uint32)Block[j + 2]) << 16) | (((Uint32)Block[j + 3]) << 24);
    }

    // Now, perform the transform on the array "x":

    // Round 1
    FF(a, b, c, d, x[0], S11, 0xd76aa478);	// 1
    FF(d, a, b, c, x[1], S12, 0xe8c7b756);	// 2
    FF(c, d, a, b, x[2], S13, 0x242070db);	// 3
    FF(b, c, d, a, x[3], S14, 0xc1bdceee);	// 4
    FF(a, b, c, d, x[4], S11, 0xf57c0faf);	// 5
    FF(d, a, b, c, x[5], S12, 0x4787c62a);	// 6
    FF(c, d, a, b, x[6], S13, 0xa8304613);	// 7
    FF(b, c, d, a, x[7], S14, 0xfd469501);	// 8
    FF(a, b, c, d, x[8], S11, 0x698098d8);	// 9
    FF(d, a, b, c, x[9], S12, 0x8b44f7af);	// 10
    FF(c, d, a, b, x[10], S13, 0xffff5bb1);	// 11
    FF(b, c, d, a, x[11], S14, 0x895cd7be);	// 12
    FF(a, b, c, d, x[12], S11, 0x6b901122);	// 13
    FF(d, a, b, c, x[13], S12, 0xfd987193);	// 14
    FF(c, d, a, b, x[14], S13, 0xa679438e);	// 15
    FF(b, c, d, a, x[15], S14, 0x49b40821);	// 16

    // Round 2
    GG(a, b, c, d, x[1], S21, 0xf61e2562);	// 17
    GG(d, a, b, c, x[6], S22, 0xc040b340);	// 18
    GG(c, d, a, b, x[11], S23, 0x265e5a51);	// 19
    GG(b, c, d, a, x[0], S24, 0xe9b6c7aa);	// 20
    GG(a, b, c, d, x[5], S21, 0xd62f105d);	// 21
    GG(d, a, b, c, x[10], S22, 0x2441453);	// 22
    GG(c, d, a, b, x[15], S23, 0xd8a1e681);	// 23
    GG(b, c, d, a, x[4], S24, 0xe7d3fbc8);	// 24
    GG(a, b, c, d, x[9], S21, 0x21e1cde6);	// 25
    GG(d, a, b, c, x[14], S22, 0xc33707d6);	// 26
    GG(c, d, a, b, x[3], S23, 0xf4d50d87);	// 27
    GG(b, c, d, a, x[8], S24, 0x455a14ed);	// 28
    GG(a, b, c, d, x[13], S21, 0xa9e3e905);	// 29
    GG(d, a, b, c, x[2], S22, 0xfcefa3f8);	// 30
    GG(c, d, a, b, x[7], S23, 0x676f02d9);	// 31
    GG(b, c, d, a, x[12], S24, 0x8d2a4c8a);	// 32

    // Round 3
    HH(a, b, c, d, x[5], S31, 0xfffa3942);	// 33
    HH(d, a, b, c, x[8], S32, 0x8771f681);	// 34
    HH(c, d, a, b, x[11], S33, 0x6d9d6122);	// 35
    HH(b, c, d, a, x[14], S34, 0xfde5380c);	// 36
    HH(a, b, c, d, x[1], S31, 0xa4beea44);	// 37
    HH(d, a, b, c, x[4], S32, 0x4bdecfa9);	// 38
    HH(c, d, a, b, x[7], S33, 0xf6bb4b60);	// 39
    HH(b, c, d, a, x[10], S34, 0xbebfbc70);	// 40
    HH(a, b, c, d, x[13], S31, 0x289b7ec6);	// 41
    HH(d, a, b, c, x[0], S32, 0xeaa127fa);	// 42
    HH(c, d, a, b, x[3], S33, 0xd4ef3085);	// 43
    HH(b, c, d, a, x[6], S34, 0x4881d05);	// 44
    HH(a, b, c, d, x[9], S31, 0xd9d4d039);	// 45
    HH(d, a, b, c, x[12], S32, 0xe6db99e5);	// 46
    HH(c, d, a, b, x[15], S33, 0x1fa27cf8);	// 47
    HH(b, c, d, a, x[2], S34, 0xc4ac5665);	// 48

    // Round 4
    II(a, b, c, d, x[0], S41, 0xf4292244);	// 49
    II(d, a, b, c, x[7], S42, 0x432aff97);	// 50
    II(c, d, a, b, x[14], S43, 0xab9423a7);	// 51
    II(b, c, d, a, x[5], S44, 0xfc93a039);	// 52
    II(a, b, c, d, x[12], S41, 0x655b59c3);	// 53
    II(d, a, b, c, x[3], S42, 0x8f0ccc92);	// 54
    II(c, d, a, b, x[10], S43, 0xffeff47d);	// 55
    II(b, c, d, a, x[1], S44, 0x85845dd1);	// 56
    II(a, b, c, d, x[8], S41, 0x6fa87e4f);	// 57
    II(d, a, b, c, x[15], S42, 0xfe2ce6e0);	// 58
    II(c, d, a, b, x[6], S43, 0xa3014314);	// 59
    II(b, c, d, a, x[13], S44, 0x4e0811a1);	// 60
    II(a, b, c, d, x[4], S41, 0xf7537e82);	// 61
    II(d, a, b, c, x[11], S42, 0xbd3af235);	// 62
    II(c, d, a, b, x[2], S43, 0x2ad7d2bb);	// 63
    II(b, c, d, a, x[9], S44, 0xeb86d391);	// 64

    m_State[0] += a;
    m_State[1] += b;
    m_State[2] += c;
    m_State[3] += d;
    for (Uint32 k = 0; k < 16; ++k) {
        x[k] = 0;
    }
}

CMkMd5Encode::~CMkMd5Encode()
{
    Zeroize();
}